Venom immunotherapy for the prevention of anaphylaxis due to hymenoptera stings is remarkably effective in patients with prior histories of such reactions. The immune state must be perpteuated by booster injections of appropriate antigen for an indefinite period. Since the natural course of insect sting hypersensitivity in un-immunized individuals is unknown, and since the long-term side effects and toxicity of such treatment are also unknown, the proposed research is aimed at determining whether patients whose reactions have been relatively mild might be safely observed without immunization; whether in vivo (skin testing) and in vitro (IgE and IgG determinations) studies can predict which individuals will require treatment; and whether venom-treated individuals have a higher incidence of abnormal physical or laboratory findings than comparable untreated individuals after a suitable period of observation. The goals thus include 1) developing a general understanding of the natural course of allergy to insect stings; 2) assessing the utility of sequential venum skin testing and antibody (IgE and IgG) determinations in predicting the risk of sting-induced anaphylaxis in children who are venom immunized or who are untreated; and 3) determining the ecomonic and psychosocial burden imposed on sting-allergic victims and their families whose medical approach to the problem is either a) prophylactic immunotherapy with venom or b) sting-avoidance and acute treatment of emergent symptoms at the time of sting-related reactions.